O-320 Cylinder Intake Port Studs

[Brian]

I am close to installing four new Lycoming cylinder kits on my O320. The Lycoming cylinders come without the studs for the intake manifold tubes to attach to. Question for the experts is do most of you buy and use the special Lyc PN 68510 studs or since these are 1/4 20 threaded holes, does it make sense to just use 1/4 20 bolts of the proper length, grip, and quality ? I can see advantages to both ways, so would appreaciate any feed back on what others do.
Thanks,
Brian

 

[Steve Pierce]

The parts manual shows bolts if I am not mistaken. That is what I have always used. They are course thread Lycoming bolts with a bit of a shoulder. Where are you talking about getting the course thread bolts?

 

[Brian]

Actually I am sitting in lab right now with about a dozen Lyc 4 and 6 cylinder engines and it’s about 50/50 ratio of the cylinders with studs on the intake verses empty holes waiting for bolts. My no suffix O-320 built in 1957 that these new cyl kits are going on did have studs and the O-320 parts manual that I have show studs with that PN I referenced in the post above, but since these cylinders are 60 years newer and have some subtle differences, I don't know that the old parts manual dictates what the new cylinders should have.
As far as where to buy them I have ordered in the past from a place in Tulsa called Aircraft Specialties which has all the Lyc engine bolts and you can order by Lyc PN which helps. But if you have a better source I am eager to know. It's sad that California has fallen off the map as far as the center of the aviation industry goes. Seems like I have to order out of state a lot these days. I did check with Spruce today and they don’t have the studs or even stock coarse thread bolts.

Link to the place in Tulsa:
http://www.aircraft-specialties.com/contact.html

 

[Steve Pierce]

Brian, If they are coming with no studs or bolts then they would probably need studs. The holes will be slightly larger for bolts than studs and my thinking would be if they were meant for studs they would come already installed like the exhaust. Was putting the intake tubes on Cathy's engine last weekend and they were bolts.

 

[andya]

Brian, If they are coming with no studs or bolts then they would probably need studs. The holes will be slightly larger for bolts than studs and my thinking would be if they were meant for studs they would come already installed like the exhaust. Was putting the intake tubes on Cathy's engine last weekend and they were bolts.

had some O-320 ovhld four years back and they came with bolts for the intakes
The individual cylinders I have replaced in the last 9 years atleast were bolts for the intakes